I am in the process of a 97 deville head gasket redo, and a friend at church posed an interesting scenario to me. He is claiming that he has repaired head gaskets on the northstar in the car by pulling the heads, using some sort of thread tool to rethread the block holes (not timeserting or any other kind of insert, just a rethread tool, I am prsuming some sort of tap kit) and buying oversized head bolts to fit the new threads. I do not have all of the technical info as to the size of the bolts etc. But does this even sound like it would work? He is ASE certified and claims he has done it before. Anyone ever tried it?